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IÔÇÖve been following roger04rtÔÇÖs posts on enriching oilhead fueling using the LC-1 by Innovate Motorsports, and I finally installed one on my 2001 R1150GS (72,000 miles). I also installed a 3.5 bar k-bike fuel regulator. On RogerÔÇÖs advice I programmed the LC-1 at lambda .96, or 14.1:1 afr.

I took the bike out for several test rides of 30-40 miles, and monitored the AFR using the gauge included with the LC-1. Here are my seat-of-the-pants impressions. I donÔÇÖt have the experience with engines running at different AFRs that Roger has, and I did not do any data logging, so these are my non-technical, subjective impressions.

The best way I can describe the engine is it just feels more ÔÇ£friskyÔÇØ to me, as if it is breathing easier (or, more correctly, less starved for fuel). It definitely has better torque in the 2500-3500 rpm range, and the on/off throttle is less abrupt. The bike surges less, but that is not completely gone (more on that later).

The bike switched to closed loop right at 3 bars on the RID. Since the 3.5 bar regulator was already producing fueling equivalent to lambda .96 the bike ran at 14.1:1 in closed loop immediately. It looked like the open loop tables had pretty much adapted to the richer closed loop mixture after a half hour of varied riding.
The bike seems to run in closed loop more than open loop. Under steady throttle on the flat and up and down moderate hills it stays in open loop ÔÇô 14.1:1. I was surprised to find that when slowing down (reduced but not closed throttle) the afr went richer (in the 13ÔÇÖs) rather than leaner. It only goes leaner under closed throttle.

My bikeÔÇÖs surging is most pronounced under steady throttle at 2500 ÔÇô 3000 rpms in the lower gears, when the engine is transitioning from power to no power (fuel to no fuel) on a level road or very slight downhill. As noted above, the afr during these periods is actually richer than 14.1:1, which suggests the surging is not the result of an overly lean mixture. Rather, it seems to this non-techie guy that the ÔÇ£surgingÔÇØ is the result of the Motronic going from a somewhat abrupt power to no-power, rather than the mixture being so lean that any unevenness in the afr of the two cylinders produces uneven power. I rode an hour this afternoon with lambda .94 (afr 13.8:1) and there was no noticeable change in the surging.

IÔÇÖd like to thank Roger for doing all of the research and experimentation, and so generously sharing it with us. Roger was also very helpful during installation and tuning of the LC-1.

It has been a fun project! It took me more than a few hours to figure out where to put the LC-1 and the junction box on the GS since it uses the under seat space differently than the RT, and then do the actual installation and wiring, not to mention installing the 3.5 bar fuel regulator. IÔÇÖm happy I made the modification, however, and IÔÇÖm looking forward to warmer weather and more experimentation with the LC-1.

It warmed uo to 40 degrees today so I reset the Motronic, programmed the LC-1 to lambda 1.01, turned on the "choke", started the bike and let it warm up. I have the 3.5 bar fuel regulator installed, so the bike was running about 6% richer than stock during open loop. While the RID was still at 2 bars the Motronic went closed loop, and I noticed an immediate and marked reduction in rpm. At closed loop the afr was right at 14.7:1 or a little leaner. (I am monitoring afr on the gauge included with the LC-1.)

It was dark, so I didn't go for a ride, but I should be able to do that tomorrow. I'll be interested to see if I can replicate this evening's results, and I'll take careful note of actual afrs during warm-up and at the switch to closed loop.

I took advantage of our 60 degree weather in NE Ohio today and took the GS out for the afternoon to experiment with different lambdas.

Taking Roger's advice I first programmed the LC-1 to lambda = 1.04 to get the bike back to what stock would be with the original O2 narrow band sensor. The engine felt more anemic, and the surging returned in the 3000 ÔÇô 5000 rpm range and was noticeable during most driving conditions except for WOT. It didnÔÇÖt take me long to realize I didnÔÇÖt want to keep it at 1.04.

Next I set lambda = .92, and that did away with most of the surging although a minor amount of hunting was still detectable in the range of 2500 ÔÇô 3500 rpm under ideal circumstances (steady throttle on level or slight downhill grade on smooth road).

I thought .92 might be a little too rich for the cat and for mileage so I bumped it up to lambda = .94 to see if I could tell much difference. I couldnÔÇÖt. The bike runs much better at .94 than it did at 1.04 ÔÇô I guess that is not much of a surprise. It is definitely is more lively and more fun to ride ÔÇô I now have to watch it a little to keep the front wheel on the ground in 1st and 2nd gear!

The Motronic adapted to the new lambda values quite rapidly. Closed loop adaptation was immediate, and open loop values seemed to change somewhat over the first 20 miles or so. It is difficult to tell what exactly what is happening open loop just looking at the gauge.

I noticed a curious thing today ÔÇô when reducing the throttle, but not closing it completely, the bike ran richer. In noticed the same thing on steep downhills under steady throttle - the mixture got richer. When accelerating the mixture would get richer until leveling off at steady speed when it would go closed loop at the programmed lambdea. My only explanation is that the Motronic must not realize the bike is going downhill, and since the engine isnÔÇÖt pulling as hard and not taking in as much air the mixture becomes richer. IÔÇÖll be interested to hear other opinions on this.

Additional info: 3.5 bar fuel regulator, valves were adjusted within last 1000 miles, new plugs were installed, and the TB sync is spot on ÔÇô verified again today. Could the bike possibly have dirty injectors (bike has 70,000 miles), or are GSÔÇÖs more prone to surging?

On my RT I get no surging at lamda =0.96 and below. But several aspects of the bikes are different. I've got dual plugs and higher compression, etc. It will be interesting to get to the bottom of it.

I've seen the same, that the mixture gets richer when you let off the throttle. Fuel can accumulate in the intake tract and on trailing throttle become available. Added to that the air is reduced a little ahead of the Motronic reducing fueling.

I had been using Bosch 4417's, but put in Autolite 3923's before going for a nice ride yesterday afternoon. I also put some Techron in the tank. Instead of focusing on how the engine was running I just decided to ride -- took some nice secondary roads, a few curves, a fair amount of hills, and 20 miles of freeway.

Boy what a difference compared to the "old" bike! There is a goodly increase in torque, particularly noticeable in the 3000-4000 rpm range where I often ride. I found myself giving it lots of throttle whenever there was the slightest opportunity, and had to be careful in 1st and 2nd gear not to let the front wheel come off the ground! I never had that "problem" before the LC-1. The "surge" seemed a little less than the day before, but I could still feel it. The wideband O2 modification is definitely a keeper. I'm running at lambda =.94 (13.8 AFR), and plan to just leave it there for a while.

A little reflection on my experience and exchanges with Roger leads me to wonder just what constitutes a surge? We talk about "surging" as though everyone knows what we mean, but I suspect it means somewhat different things to different people. Do conditions matter, for example, is it detectable in normal riding vs. optimal conditions for surging? Is there a way to quantify the surge -- how strongly it is felt, at what rpms, in what gears, etc.? Yesterday I could detect what to me was a slight surge, but I suspect others may not notice it or think of it surging. Since we use surging as one criterion of how our bikes are running it might be good to be more specific about what we mean.

With the cold and snow around here I've been looking at the Stock O2 sensor.

This is just some, "isn't that interesting" stuff. The stock O2 sensor is two devices in the same package. One device is a heater to make sure the second device, a lambda cell, is hot enough to function properly.

Stock O2 Sensor Heater
ÔÇöOn the R1100 and R1150, +12V to the heater in the O2 sensor comes from the same circuit that powers the fuel pump and fuel injectors.

ÔÇöThe ground connection for the O2 heater is hardwired to ground on the R1100 so the heater comes on as soon as the engine starts.

ÔÇöOn the R1150 the "ground" wire for the heater is connected to a switch in the Motronic that waits the motor to be running for a minute or two before it turns the heater on. I can only guess why. It may be for reliabilityÔÇöheater is off till it is warmed by the exhaust so the heater isn't cold shocked at startup.

ÔÇöA malfunctioning heater could keep the sensor from working well. In my test setup I keep an LED connected to the heater so I know if it's on.

Stock O2 Sensor Lambda Cell
When hot (750F or more for a workable signal) this cell puts out about 800 mV when there is no oxygen in the exhaust (mixture richer than 14.7:1). When it detects any oxygen in the exhaust, mixture leaner than 14.7:1, it outputs only 100mV. So the O2 sensor only tells the Motronic if the exhaust gas has, or does not have any oxygen in it

ÔÇöOn the R1100, the low side of the lambda sensor is connected to ground. The high side connects to the Motronic.

ÔÇöOn the R1150 (and 1200s too) both the high and low wires connect to the Motronic. There is no direct connection to ground. Inside the Motronic is a very clever circuit that "adapts" to the signal swing. Even if the lambda sensor isn't working well the Motronic manages to find the 14.7:1 changeover point. I've cut the signal by 2/3 and the Motronic MA 2.4 manages to find a workable signal.

ÔÇöI'm wondering how many 10-20 year old lambda sensors are still functioning properly. It really is a part of the bike that we're blind to. And to make matters worse, not only are we blind to what it's doing, it is the Motronic's most important sensor for good running qualities. If its bad you'll run badly.

I'm wondering how many 10-20 year old lambda sensors are still functioning properly. It really is a part of the bike that we're blind to. And to make matters worse, not only Re we blind to what it's doing, it is the Motronic most important sensor for good running qualities. If its bad you'll run badly.

9 years old in my case, if I remember correctly. After replacing plugs with Autolite Iridium, tuning, syncing etc., I replaced the O2 sensor. I believe it was one of several steps that helped cure the surge.

The fuel injectors I had sent off for cleaning (RC Engineering) came back today. The report showed they had flow rates of 315 and 294 cc/min before cleaning; and 321 and 319 cc/min respectively after cleaning. The 21 cc/min difference between cylinders before cleaning seems like a lot, which I believe could account for the slight surge I still had after installing the RC-1.

So I installed the cleaned injectors and went for a ride, syncing the TBs after the engine was fully warmed up. The surging is now gone! I had forgotten just how smooth and torquey the GS is with the richer fueling. The LC-1 transformed the bike. I rode like a hooligan coming home ÔÇô big smile on my face, 30 degree weather notwithstanding.

Thanks Roger for your help every step of the way. For me, this is a modification well worth doing.

I finally was able to take a ride yesterday and evaluate the performance of my '04 R1150RT after installation of the LC-1 with wideband O2 sensor. I am also using a 3.5 BAR fuel pressure regulator. Ride was mostly on I84 from Baker City to ontario and back (135 miles) with weather temp of 45F bright sun calm winds. Should also mention that for this test ride I have 13.5:1 AFR dialed in on the LC-1.

After allowing some time for Motronic learning I began some throttle role ons in 6th gear letting revs drop to 2500 then rolling on the throttle. I must say the results were impressive to say the least. The motorcycle would pull very strongly and quickly right up to over 100 mph with no need to downshift into 5th. This is a huge improvement as I have done most of the 41K miles on this bike continuously in 5th gear on interstates as well as secondary roads. Looks like 6th gear is finally going to get a lot of use. The other thing of note was the very smooth idle. In 8.5 years I have never seen or heard this bike idle with such absolute smoothness but the over the road smooth running was almost unreal and I had to keep an eye on the speed as I found myself cruising along at 85+ in 6th. Don't want to get stopped in Oregon at those speeds because it can cost.

I would recommend the LC-1 to anyone with one of these lean running motorcycles as the cost is minuscule compared to the increase in very smooth performance.

Since this thread is very long now I'd like to mention that although I made several dozen tests to make sure that the LC-1 worked harmoniously with the Motronic, the installation is in most ways pretty easy. Anyone wishing to make this mod doesn't need to remake any of my tests.

If you get an O2 sensor connector, wire it per the diagram below and program 6 numbers with a PC, it will just work.

I would be happy to provide e-mail support this year for anyone who wants to give it a go. The outlay for all the parts is less than $200.

I know that this is not within everyone's skill set but the diagrams below are what needs to be done. Pull the various LC-1 cables into a plastic box and connect the wires.
RB

Since the LC-1 approach to richening the engine fuel to air mixture does so many good things but is a bit of work to install, I wanted to see if there was an easy way to use the stock Narrowband sensor and "pull" it a little richer than it is designed to run normally. It turns out that after some measurements, and tests, it is possible to do just that--get up to 6% richer fueling using the stock O2 sensor. Here's the story ...

A couple of months ago I installed a second bung in the exhaust of my R1150RT. I wanted to have both a Wideband O2 and a Narrowband O2 installed and running at the same time. The idea was to let the Motronic use the Narrowband in the usual way while I recorded the results of Motronic/Narrowband by monitoring the Wideband. In other words using the Wideband to spy on the Narrowband. Second Bung Install.

The Wideband showed that the Narrowband/Motronic pair kept the Closed Loop fuel right at lambda=1 (AFR 14.7:1).

Then I wanted to see if there was some kind of circuit that could be inserted in series with the Narrowband to richen the mixture without having to add an LC-1. The Narrowband sensor is well designed and has a big change of voltage right at Lambda=1. Just a bit leaner and its output drops to 100mV. Just a bit richer and its output jumps to 800mV.

The exact rich output voltage increases from about 700mV at 14.6:1 to about 900mV at 13.8:1. That is a small voltage change for a large mixture change, which means it is too small a change for the Motronic to work with.

Compounding matters, in the rich zone, from 700 to 900mV, the voltage changes as the exhaust gets hotter from higher engine load. Another way to say the same thing is that the voltage that corresponds, for example, to 14.1:1 (slightly rich) changes with engine loading. Compounding the problem further, the Motronic has a clever circuit that figures out if the voltages have been shifted. It uses that circuit to ignore simple shifts of the O2 signal.

I also built a test harness which allowed me to add circuits in series with the the stock O2. I tried a dozen different ideas, including some patented circuits from nightrider.com that work on Harley Davidsons. Nothing worked.

Over the last year, I've gotten to know the owner of nightrider, Steve Mullen. One of his Harley O2 richening products has a microprocessor inside. As designed for the Harleys, it didn't work either. But a couple weeks ago, we discussed and agreed on a different algorithm. Steve coded it up and sent me a new "chip" just for BMWs.

To make a long story short, the new "chip", with some other circuit changes, will pull the Narrowband sensor several percent into the rich zone. The way it works is that the microprocessor module measures the stock O2 sensor voltage, filters it to reduce noise, and then alters the voltage transfer function so that the signal it sends to the Motronic looks like a normal Narrowband sensor that is switching at a richer lambda (range is 0-6% richer).

As it is designed (proto with many extra wires, below) you unplug the stock O2 and plug this device between the two stock connectors. There is a ground wire to connect also. There is already power in the O2 sensor cable so no power connection or new fuse is required. The final product will be about 1/2" x 1" x 3" with two OEM connectors, plus one ground wire.

I have test ridden this circuit at 13.8, 14.1, 14.3 and 14.45 and will post some charts and other data tomorrow.

For those interested, PM me. We will build a couple of modules for pre-production trials for R1150XX with Motronic MA 2.4. Assuming everything works it will then go into production.

RB

Note: If the connectors are made compatible, this would work on any R1100, R1150, R1200 (2 needed).

Prototype test cable harness and small O2 processor device. Final product would be just the processor, two thin cables with OEM connectors and a ground wireÔÇöa simple plug 'n play solution.

Below is a plot of the O2 Circuit with Narrowband at the bottom of the chart, and an LC-1 at the top. The LC-1 is set to 13.8 (the red dotted line) but it would have the same look at any programmed AFR. The thing that jumps out is how solidly the Motronic locks the LC-1 onto the target AFR.

In the bottom chart the O2 Circuit & Narrowband was set to 13.8:1. The result was 14.0:1 at hot idle (the red line) and 13.6 (the blue line) at 80MPH cruise. Different loads resulted in different Closed Loop AFRs. Interestingly higher loads lead to richer mixtures which isn't terribleÔÇösome might even say it's a good feature. (Hotter exhaust makes the O2 sensor produce a given voltage at a richer mixture.)

This means the spread was ??0.2 AFR between idle and 80 mph and that was with the narrowband pulled a long way off its design point. There are some additional data sets below the charts. (Note that the first few minutes is very rich. That's the Open Loop Cold-Start Fueling.)

After two more test rides, I have a good data base at three settings. Setting 5, 7 and 8 are actual and setting 6 is estimated but I will ride it later. The data look pretty good. The curves for the various settings all look like the one above. Here are the different results:

It is my opinion that most bikes will run great at setting 6 or 7. An important point here is that when you richen closed loop AFR, the open loop fueling gets richer too, coming along for the ride through a process known as Adaptation.

As I said earlier, because of the heating, the mixtures get a little richer with higher loads. Looking at those numbers above, the lean end of the range occurs at idle and the rich end of the range happens at 80 mph.

There are still a few small adjustments to make to voltage levels and to the algorithm. Then we find sources for the OEM O2 connectors, then a few pre-production units.

I noticed something interesting on my LC-1 equipped 2001 R1150GS. I have Lambda set at .94 (13.8:1 AFR). As long as I ride below 4000 rpms the engine hovers right around 13.8 on level going and modest uphills. However, above 4000 rpm the AFR goes up to 14.4 on level going while maintaining steady speed. If I increase throttle enough for the engine to pull a little, the AFR drops back to 13.8.

I've ridden several hundred miles, so I wouldn't think the Motronic is still learning. And even if it was, I would expect steady speed on level going to be running in closed loop, which should be 13.8. I've observed the above pattern in gears 1, 2 & 3. I'll need to get on a bigger highway to test it out in the upper gears.

Could it be that the Motronic is designed to lean out the mixture when it thinks the bike is cruising (steady throttle, above 4000 rpms)? I have no way of knowing for certain when the bike is in closed vs. open loop, since the only feedback I'm getting is the AFR gauge.